1. Field of the Invention
The present invention relates to a navigation device which can recognize a road lane of a running vehicle, and a road lane recognition method thereof.
2. Description of Related Art
Generally, a navigation device is to provide route information to the driver's destination. A driver can see a map displayed on a terminal of a navigation system or listen to voice message while driving a vehicle. The navigation device functions to combine location information using GNSS (global navigation satellite system) and geographic data of a digital map and display a vehicle position on a road displayed on the map.
However, a conventional navigation device can not indicate information about a precise road lane occupied by the vehicle. That is, the conventional navigation device can guide only a point of time when the vehicle turns left or right on a route to a destination, but cannot guide the route on the basis of the vehicle's drive position by road lane. For example, in case that the vehicle which intends to turn left runs on other lanes except the first lane, the conventional navigation device does not inform of lane change. Therefore, there is inconvenience in that a driver has to change the lane after determining the vehicle location and the actual road lane occupied by the vehicle.
In order to solve the inconvenience, there has been proposed various methods such as a road lane recognition method using RFID (radio frequency identification) sensors laid under the road, and a road lane recognition method using cameras.
However, in case of the road lane recognition method using RFID, since the RFID sensors should be laid under all roads, this method has some problems such as construction difficulties and maintenance costs. Further, in case of RFID using communication network, there is also another problem that a RFID reading rate may be deteriorated according to ambient climate conditions and vehicle speeds.
In case of the road lane recognition method using cameras, this method has been mainly developed as a lane departure warning system, and thus it can only recognize the road lane but cannot recognize an absolute lane on which the vehicle is running. Furthermore, in case that it is foggy or snowing heavily, it is impossible to recognize the road lane.